Encoderless Predictive Speed and Torque Control of an Induction Motor

Recently, model predictive control (MPC) has gained popularity in the control of power converters and electric drives. In this paper, the advantages of two MPC strategies are combined, and a cascaded encoderless predictive speed and torque control (PSTC) based IM drive is proposed. The use of linear controllers in the speed control loop of the traditional PTC strategy degrades the speed control performance in the presence of unknown disturbances and mechanical parameter changes. Also, eliminating encoders from electric drives reduce the cost, size, and hardware complexity, while increasing reliability and mechanical robustness. For this purpose, an extended Kalman filter is designed to estimate the flux, speed, and load torque information required for encoderless PSTC. The proposed electric drive system is validated by simulation studies under different operating conditions, resulting in good control and estimation performance.